The present invention relates to the tool change mechanism art in which a plurality of tools for use at a work station of a machine tool are stored in a tool storage magazine. In mechanisms of this type, a tool transfer member is commonly provided for extracting a selected tool from the magazine and transferring it to the work station and for likewise removing the previously used tool from the work station and returning it to the magazine.
Tool change mechanisms of this type are well known as exemplified by a tool interchanger 31 illustrated by two hinged arms 33 and 34 as well as a slidable drive rod 44 in U.S. Pat. No. 3,492,717. A tool changer with hinged arms 36 and 37 is also illustrated in U.S. Pat. No. 3,608,188. Tool changing arms without hinging are shown at 28 and 29 in U.S. Pat. No. 3,608,185 and at 45 in U.S. Pat. No. 3,760,491 where a scissors type tool changer is illustrated as well as in U.S. Pat. No. 4,087,901. In U.S. Pat. Nos. 3,587,873, 4,288,909 and 4,164,290, tool change arms are indicated at 32, 298 and 46, respectively, wherein the arm members are of a one piece construction. While the foregoing tool changing arms offer a variety of tool change operations and many of them are efficient in their operation, there still exists a need for a tool change arm which can reduce the amount of time required to remove a used tool from a spindle in a work station and replace it with a new tool. Although the time required to change a tool averages about six seconds, a machining operation is not taking place. If this time could be reduced it could reduce the time that the machine is not machining. For example, when the machine is not working during a normal machine tool change, the following steps are taking place: the changer is rotated to the spindle tool change position; the changer then clamps onto the tool in the spindle; the tool is pulled out of the spindle; the old tool is rotated away and a new tool is rotated into the spindle area; the new tool is pushed into the spindle; the tool is unclamped in the spindle from the changer; and the changer is rotated to the tool storage change position.
It is a general advantage of the present invention to provide an improved tool change mechanism which will substantially reduce the amount of time a tool machine is not working in order to effect the changing of tools. A further advantage is to provide a tool change mechanism that is simple in its construction and is readily adaptable to existing tool machines and tool magazines. It is a further advantage to provide a tool change mechanism which is durable in its construction yet can afford a multiplicity of positions for the tools being interchanged between the magazine and the spindle head.